Predictive Maintenance, or PdM, programs in industrial plants are frequently implemented by assigning a technician to use portable instrumentation, such as a vibration analyzer, an ultrasonic gun, and/or an IR camera, along a predetermined route to collect data related to the operation of the equipment on this route. This information, in turn, may then be used to diagnose problems or potential problems associated with the health and/or operation of the equipment. An example system and method for data collection relevant to machine operating conditions is disclosed in U.S. Pat. No. 6,078,874, entitled “Apparatus and Method for Machine Data Collection,” the contents of which are incorporated by reference herein.
For example, a PdM program may include a technician carrying a data acquisition unit, e.g., a vibration analyzer, to each machine located along a defined route. Upon reaching a particular machine to be analyzed, a vibration sensor, such as an accelerometer, is physically coupled to the machine at one or more measurement locations. Frequently, the data to be acquired at each measurement location is specified as part of the route instructions. The vibration sensor then receives vibration data from the measurement locations, and may output this information to the data acquisition unit for processing.
Historically, the portable vibration analyzers used in PdM programs have been dedicated instruments designed as a single unit which performs all the necessary functions for navigating a route of machines, acquiring and reviewing data, and storage of the data for later transfer to a host workstation. The software to perform detailed diagnostic reviews of the data reside on the host workstation. The vibration analyzers were designed with integral displays and keypads to enable the operator to control the operation of the instrument. The internal components of these conventional vibration analyzers typically include a central microprocessor, signal conditioning and data acquisition circuits, and digital signal processing software and/or hardware. This type of design has been used by virtually every manufacturer of portable vibration analyzers. The popularity of the single unit design has been based on the desire to offer a rugged, compact and portable, high performance instrument with the lowest production costs. Instruments of this design have been sold by such manufacturers as Emerson\CSI, SKF, Pruftechnik, GE\Commtest, and others for the past 25 years.
Clearly, the conventional single unit design offers many advantages; however, there are also disadvantages to this configuration. The portability of the unit and the size of the display/keypad on the front panel present conflicting requirements. Vibration time waveform and spectral data may include 400 to 25,600 values and are viewed in a graphical format. Viewing such graphical displays on a small screen is challenging. Additionally, because of the variety of functions present in the analyzers, control buttons and alphanumeric keypads would be desirable. However, complex keypads will generally not fit on the front panel space available. As a result, the size of the instrument is often controlled by the space designed for display and control functions. Clearly, the two primary design characteristics of the instrument that impact its convenience in use by the operator, are at odds with each other. It is desirable for the field technician who may be collecting data from 400-800 locations in a typical shift to have a small, highly portable, instrument; and the operator is often willing to sacrifice screen size and user interface buttons because he is performing very repetitive tasks with the expectation that the analysis of this data will be performed at the host workstation. However, the second primary use of the analyzer is to perform troubleshooting on machines to determine if a problem exists and to identify the fault conditions. This work is often focused on one machine and may involve a large number of measurements which are reviewed in the field. One measurement may lead to others until the source of any abnormal conditions are understood and documented. This analysis process is more properly performed with a more detailed display and control interface. Thus, it is difficult to satisfy the goal of both simple portability and the ability to perform more detailed analysis fully with one instrument.
Another drawback to the single unit design has been inflexibility and complexity of the development process. Each design is a dedicated computer with special data acquisition and processing hardware. Each time a new product or a new generation of an existing model is developed, another development cycle of typically 1-3 years is required, and at considerable expense. The extended development cycle for a new analyzer is a deterrent to innovation because of inherent limitations of the existing hardware platform which typically have a product lifetime of 5-10 years to recoup the development costs. The current practice for introducing new laptop or tablet computers, PDAs, and cell phones is rapid innovation resulting in new versions with new capabilities available each year. The PdM instrument marketplace does not represent the volume of sales that drives the development of commercial computing and communications electronics. However, the introduction of a new design paradigm for PdM instrumentation can lead to a faster design cycle which results in a more flexible and dynamic product evolution.
Yet another drawback to the conventional single unit design is the occasion when the technician wishes to avoid hostile conditions during data acquisition and processing. Typically, the vibration analyzer and the vibration sensor are coupled together by a signal cable which is relatively short to make it easy to transport. In most cases, the technician will be within 3-8 feet of the measurement location during data acquisition and processing. In circumstances where the access to the specified measurement location on a particular machine is cumbersome, uncomfortable, or even unsafe for the technician, it may be desirable to move to a position at a greater distance during data collection. Accordingly, there exists a need in the art for a predictive maintenance system that includes a data acquisition unit in wireless communication with one or more operator control units that allow the technician to remotely control the data acquisition unit, as well as to receive acquired and/or processed data from the data acquisition unit.